Immunoglobulin D

Immunoglobulin D ( IgD ) has a Y-shaped antibody molecule at a concentration of 0.03 mg / ml - occurs in the serum of vertebrates ( other than birds ) - which corresponds to less than 1 % of human serum immunoglobulins. Its exact function is still unknown. IgD is found on B lymphocytes. In its free form, it is broken down very rapidly.

Properties

In his antibody function is the IgD part of B lymphocytes and the membrane is produced, when the B cell is leaving the bone marrow. Are produced after complete activation of the B cell both IgD and IgM. IgD binds and activates mast cells and basophils.

The antibody is a monomer (a single molecule), which consists of two long, "heavy" protein chains (also called H chains of English heavy) and two short, "light" chains (also called L- chains, light of English) there. It has the shape of a " Y". Are the binding sites ( paratopes ) with which they can bind to the epitopes of the antigens (foreign bodies, for example, specific surface structures of bacterial cells ) at the short ends of the Y. The molar mass of the H chain is 69700 daltons which the whole molecule 160000 Dalton.

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